2013 Annual Report
Improved smooth bromegrass strain increases beef cattle gains on pastures. Improved cool-season grasses are needed in the Midwest and Northern Great Plains to improve beef cattle gains per acre and profitability. An experimental smooth bromegrass strain developed from the cultivar ‘Lincoln’ by four generations of recurrent breeding for increased forage yield and digestibility by an ARS geneticist at Lincoln, NE was evaluated in a replicated grazing trial with beef yearlings for three years by ARS and University of Nebraska scientists. Cattle grazing the experimental bromegrass strain had 3-year average daily gains of 3.1 lbs per head per day during spring grazing. The 3-year average body weight gain of 349 lbs per acre during the spring grazing season was 12% greater than that for the widely used smooth bromegrass parent cultivar Lincoln demonstrating that the genetic improvements in smooth bromegrass can have significant economic value when used in well managed pastures. The smooth bromegrass experimental strain is in seed increase for potential release as a new cultivar. It can be used to meet the demand for improved cool-season pastures in the Midwest and Northern Plains.
Identified a total of 342 class III peroxidases genes in the switchgrass genome. Work with other grasses have shown that increases in the levels of specific class III peroxidases are associated with improved resistance to herbivory by piercing-sucking insects. Such information is unavailable for switchgrass. In this work performed by ARS researchers at Lincoln, NE, in collaboration with University of Nebraska scientists, the presence or absence of all the class III peroxidases was documented in switchgrass tissues at different stages of plant development. Using this data, it is now possible to identify specific switchgrass peroxidase genes that are involved in the plant’s response to insect herbivory. Data obtained by these new analytical methods can be used by plant breeders and other researchers to develop switchgrass strains with improved resistance to piercing-sucking insects.
Improved bioenergy type switchgrass cultivar with high biomass yield tested and increased for use in the northern half of the USA. Switchgrass cultivars for the northern half of the US have been limited to upland ecotype switchgrass cultivars because available lowland cultivars have poor winter survival in the region. Lowland switchgrass cultivars have the potential to produce greater biomass yields if they had better winter survival. A new lowland type switchgrass cultivar ‘Liberty’ will be released in 2013. Liberty which was developed by ARS researchers at Lincoln, NE by crossing northern upland and southern lowland plants followed by three generations of breeding for winter survival, high biomass yield, and low stem lignin concentration. Over a three year period in trials in NE, WI, and IL, Liberty had excellent winter survival and in eastern Nebraska and northern Illinois had biomass yields that were 2 tons per acre greater than the best available released upland cultivars. The experimental strain is in the ARS cultivar release process and has been planted in a Foundation seed increase field. It will be the first bioenergy type cultivar for the Midwest and the northern Great Plains and will likely also be used in the Northeast states. When processed in a biorefinery, the increased biomass yield will result in an additional 160 gallons of ethanol per acre which could fuel an economy car for 5000 miles.
Watrud, L., Reichman, J., Bollman, M., Smith, B., Lee, E., Jastrow, J., Casler, M.D., Collins, H.P., Fransen, S., Mitchell, R., Owens, V.N., Bean, B., Rooney, W.L., Tyler, D.D., King, G.A. 2012. Chemistry and microbial functional diversity differences in biofuel crop and grassland soils in multiple geographies. BioEnergy Research. 6(2):601-619.
Mitchell, R., Vogel, K.P., Sarath, G. 2012. Predicting the field establishment of perennial grass feedstocks: progress made and challenges ahead. Biofuels. 3:653-656.
Uden, D.R., Mitchell, R., Allen, C.R., Mccoy, T., Guan, Q. 2013. The feasibility of producing adequate feedstock for year–round cellulosic ethanol production in an intensive agricultural fuelshed. BioEnergy Research. doi 10.1007/s12155-013-9311-x.
Bowman, M.J., Dien, B.S., O'Bryan, P.J., Sarath, G., Cotta, M.A. 2012. Comparative analysis of end point enzymatic digests of arabino-xylan isolated from switchgrass (Panicum virgatum L) of varying maturities using LC-MS(n). Metabolites. 2(4):959-982.
Saathoff, A.J., Donze, T., Palmer, N.A., Bradshaw, J., Heng-Moss, T., Twigg, P., Tobias, C., Lagrimini, M., Sarath, G. 2013. Towards uncovering the roles of switchgrass peroxidases in plant processes. Frontiers in Plant Biotechnology. 4:1-12. doi 10.3389/fpls.2013.00202.
Kovacs, F., Sarath, G., Woodworth, K., Twigg, P., Tobias, C.M. 2013. Abolishing activity against ascorbate in a cytosolic ascorbate peroxidase from switchgrass. Phytochemistry. doi 10.1016/j.phytochem.2013.05.016.